It is known that ionic or plasmic type space electric thrusters, which have been used for long for thrusting spacecrafts, have the advantage of a high specific impulse allowing a same speed increment to be obtained for a lower ergol mass than a chemical thruster. On the other hand, the dry mass of an ionic or plasmic jet electric thruster is generally higher than that of a chemical thruster. Now, for a determined ergol mass, any increase of the dry mass results in a reduction of the speed increment.
One of the causes of the importance of the dry mass of such a space electric thruster is due to the need to orient the direction of the thrust thereof. Indeed, a space electric thruster being bulky and expensive, it is not economical to arrange several of them in order to allow a pulsed operation to be implemented, so as to simultaneously provide the thrust and the directional steering.
In order to overcome such a drawback, it has been contemplated arranging such a jet electric thruster on an orientable platform. However, such a platform should bear the whole thruster and the connections with the supply system for ergol being used as a fuel for generating the jet from said thruster. This leads to a significant increase of the dry mass of the thrusting system, while the thrust orientation freedom remains limited to about 30 degrees, which is not always sufficient for all the phases of a space mission.
Furthermore, it has also been contemplated to deflect the jet of a space thruster through modifying the electric or magnetic field at the outlet thereof. However, only a few degrees of orientation freedom for the thrust direction can be achieved.